Space-current device



Dec. 11, 1934. E, L, BOWLES 1,983,838

SPACE CURRENT DEVICE Filed May 51, 1930 Patented Dec. 11, 1934 SPACE-CURRENT DEVICE Edward Lindley Bowles, Wellesley Farms, Mass. Application May 31, 1930, Serial No. 457,993

3 Claims.

The present invention relates to space-current devices, like vacuum tubes, and more particularly to the grid elements of such tubes.

The invention will be explained in connection with the accompanying drawing, showing a diagrammatic view illustrating one embodiment of the invention.

The vacuum tube is shown as having a chamber or vessel 2 in which are contained three electrodes, namely, a filament 4, a grid 6 and a plate 8. The plate is shown as of the conventional cylindrical form, and the filament 4 as passing through the walls of the chamber 2 at 10 and 12. The grid element 6 is alone of novel construction, and is shown as in the form. of a curved or helical tube. In this form it has a number of advantages.

According to the illustrated embodiment of the invention, one end 20 of the grid element 6 extends outside the tube at 16, the other end 22 being within the tube and closed. It is possible to drive air under pressure into the open end 20, which will cause the tube to expand and contract in accordance with the degree of pressure. Because of this expansion and contraction, the plate current will naturally vary, and this,in turn, may be used as a measure of the pressure, or it may be used for other purposes.

It is obvious that the invention is capable of considerable modification and change by persons skilled in the art, and all such are considered to be within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A space-current device having a chamber, and a filament, a grid and a plate in the chamber, the grid comprising a coiled tube open at one end and closed at the other end, and means for supplying a fluid under pressure into the open end of the tube.

2. A space-current device having a chamber, and a filament, a plate and a hollow control electrode in the chamber, the control electrode being open at one end and closed at the other end, and

means for forcing fluid under pressure into the open end of the control electrode to cause the control electrode to vary its position relative to the filament and the plate.

3. A space-current device having a chamber, and a filament and a plate and a control electrode in the chamber, the control electrode comprising a helical tube the axis of which is substantially parallel to the plate, the control electrode being open at one end and closed at the other end, and means for forcing fluid under pressure into the open'end to cause the diameter of the helical tube to vary in order to vary the position of the coils of the helical tube relative to the plate. 

